“There's a 24-hour fitness room on the first floor, which you can access with your room key.”
You work at a hotel. A guest is checking in. You're telling him about some of the things that your hotel offers. You explain where he can go to exercise.
There's a 24-hour fitness room on the first floor, which you can access with your room key.
Something that is open and available all day and night is sometimes called "a 24-hour ___". Here are some examples:
- a 24-hour customer service line
- a 24-hour convenience store
A "fitness room" is like a small gym. It has a few exercise machines, an area for stretching, etc. Apartment buildings, hotels, and offices sometimes have fitness rooms.
Larger facilities for working out are called "gyms".
Use the word "which" to add an extra description of something:
I'm the creator of the Women's International Network, which is a networking group for female professionals around the world.
Notice that there's a comma before "which". This shows that you're giving extra information. The listener doesn't need this information to figure out which network you're talking about.
If you're talking about a person, don't use "which". Use "who".
If you have the key to open the door to a room, you can get into the room. Another way to describe this is that you can "access" the room with the key.
Aside from a physical key, you can also "access" rooms, computer files, and other things using passwords, codes, ID cards, etc.
The key that you get when you stay at a hotel is called your "room key". You can call it your "room key", even if it's in the shape of a card instead of a metal key.